Inhibition of gas fading with an alkali metal salt of phthalic acid



United States Patent() INHIBITION OF GAS FADING WITH AN ALKALI METAL SALT OF PHTHALIC ACID Henry Charles Olpin, Edmund Stanley, and Anne Elizabeth McCarthy, Spondon, near Derby, England, as signors to British Celanese Limited, a corporation of Great Britain No Drawing. Application December19, 1951, Serial No. 262,472

Claims priority, application Great Britain January 18, 1951 1 Claim. (Cl. 8-61) This invention relates to improved coloured textile materials comprising cellulose acetate fibres or fibres of another cellulose ester of an organic acid or of a cellulose ether, and especially to materials of this character which are of good resistance to gas-fading.

It is well known that textile fibres of cellulose acetate, coloured with certain dyes, are liable to undergo a change of shade when subjected to the action of combustion products of coal gas. The phenomenon is commonly referred to as gas-fading and is particularly associated wth materials coloured with 1:4-diamino-anthraquinone and its simple derivatives, e. g. l:4-di(alkylamino)-anthraquinones; it is almost certainly due to the oxides of nitrogen content of the combustion products and can be simulated by other atmospheres containing nitrogen oxides. This fading trouble usually occurs while goods are in store and but rarely during the normal use of the goods, especially goods which are regularly laundered. Various substances have been proposed for incorporation into coloured cellulose acetate textile material for the purpose of reducing or preventing gas-fading. Many substances are effective in reducing or substantially preventing gas-fading but this is not the only test which as substance must pass if it is to be commercally acceptable. It is necessary that a substance used should not have any deleterious effect on the textile material. For example the substance should not adversely affect the handle of the material. Again it must not itself discolour under the action of light and must not adversely affect the fastness to light of dyes on the material.

We have found that the alkali metal salts of phthalic acid are of outstanding value for incorporation in cellulose ester or ether materials liable to gas-fading in that, while effective in reducing or preventing gas-fading, they have substantially no adverse effect on the fastness to light of either the dyes normally used for colouring cellulose acetate fibres or the direct cotton colours largely used for the dyeing of cotton or regenerated cellulose. On the other hand triethanolamine, a substance which has been largely used as an anti-gas-fading agent,- considerably reduces the fastness to light of many direct cotton colours and of some of the dyes commonly used for the dyeing of cellulose acetate, for example 2:4-dinitro4-hydroxy-diphenylamine and l-amino-4-hydroxy-anthraquinone. The same applies to other nitrogenous substances which have been suggested, for example N:N-diphenylethylene diamine which has the further disadvantage of itself discolouring under the influence of light, a disadvantage not shared by alkali metal salts of phthalic acid.

The alkali metal salts of phthalic acid are thus of particular value for reducing gas-fading in the case of textile fabrics, e. g. furnishing fabrics, containing both cellulose acetate fibres and fibres of natural or regenerated cellulose coloured with direct cotton colours. They are moreover cheap and," being soluble in water, readily incorporated in a textile fabric. Their water-solubility 2,758,002 Patented Aug. 7, 1956 ice results in the anti-gas-fading efiect being largely lost when the textile is washed but this is of little importance in the case of materials which are not normally Washed (e. g. furnishing fabrics andliningsfor mens suits); further it should be borne in mind, as indicated above, that textiles which undergo regular laundering seldom give trouble by reason of gas-fading.

The alkali metal phthalates are further outstandingly effective in reducing or preventing gas-fading, being greatly superior to the generality of salts of weak or moderately weak acids. Thus the sodium salt of naphthalic acid is greatly inferior to sodium phthalate.

The present invention includes textile material consisting of or containing fibres dyed with dyes not normally resistant to combustion products of coal gas, the said textile material having an alkali metal salt of phthalic acid incorporated therein.

The alkali metal of the salt may be sodium or potassium and the di-alkali metal salts are preferred.

The proportion of the salt incorporated in the textile material may be quite small, for example 0.25 or 0.5 to 2%. About 1% is a very satisfactory proportion, being highly effective for the purpose in view and without substantial effect on the handle of the material.

The textile material may be woven or knitted fabric consisting wholly of fibres (whether staple fibres or continous filaments) of cellulose acetate or other cellulose ester or ether or in part of such fibres and in part of other fibres, for example silk, wool, or fibres of natural or regenerated cellulose. The invention particularly contemplates textile fabrics having an alkali metal phthalate incorporated therein and comprising cellulose acetate or other cellulose ester or ether fibres coloured with the aid of l:4-diamino-anthraquinone, 1-amino-4-hydroxy-anthraquinone or an N-alklylor N-arylor N-alkyl-N-arylderivative thereof (or a nuclear substitution product of such anthraquinone derivative), for example 1:4-di- (methylamino) -anthraquinone, 1 :4-di-(betahydroxyethylamino) 5:8 dihydroxy-anthraquinone, 1 amino 4- phenylamino anthraquinone, 1-methylamino-4-phenylamino-anthraquinone, and the blue dye mixture obtainable by the action of equimolecular proportions of methylamine and mono-ethanolamine on leuco-quinizarin. The said coloured fibres may be alone in the fabrics or they may be in conjunction with other fibres, especially cellulose fibres coloured with direct cotton colours. The fabrics may be for instance a patterned furnishing fabric woven from continuous filament cellulose acetate yarns and cotton yarns.

The incorporation of the alkali metal phthalate in the textile material may be effected by impregnating the material with an aqueous solution of the salt and thereafter drying the material. The proportion of salt incorporated may be regulated by suitable choice of concentration of the aqueous solution and of the proportion of solution left on the material before drying. The aqueous solutions may advantageously be applied by padding on a padding mangle, the pressure of the squeeze rolls being adjusted so as to leave the desired proportion of the salt solution on the material. Thus, using a 2% solution of sodium phthalate and adjusting the squeeze rolls so that the material retains 50% of its Weight of the solution, the material will contain 1% of sodium phthalate after drying.

The invention is illustrated by the following examples:

Example I A satin-weave fabric of continuous filament cellulose acetate yarn is dyed with 0.2% by weight of the blue dye mixture obtainable by the action of a mixture of equimolecular proportions of methylamine and mono-ethanolamine on leuco-quinizarin. The dyed fabric is then paddedwith a 2% aqueous solution of di-sodiurn phthalate so that it retains a quantity of the solution equal to about half its dry weight. The fabric is then dried on a stenter. The resulting fabric is highly resistant to fading by combustion products of coal gas.

Example II A Jacquard fabric woven from equalweights of continuous filament cellulose acetate yarn and cotton yarn is dyed on the winch with the following mixture of dyestuffs:

0.1% 1-methylamino-4-phenylamino-anthraquinone (commercial powder 30% strength) 0.3 2 nitro 4 chlor-4'-methoxy-diphenylamine (commercial powder 30% strength) 0.15% Chlorantine Fast Blue GLL (Ciba) 0.4% Chlorantine Fast Yellow 2RLL (Ciba).

treatment the resulting fabric has a much superior resistance to gas-fading while the fastness to light of the direct cotton colours is substantially unimpaired. On the other hand if triethanolamine is applied in place of the disodium phthalate the light fastness of the direct cotton colours is substantially reduced.

Having described our invention, what we desire to secure by Letters Patent is:

A method of improving the resistance to combustion products of coal gas of dyeings on textile materials comprising filaments of an organic derivative of cellulose, selected from the group consisting of cellulose esters and cellulose ethers, produced with the aid of dyes for said organic derivative of cellulose which are obtained by the action of a mixture of equimolecular proportions of methylamine and mono-ethanolamine on leuco-quinizarin and which are not normally resistant to combustion products of coal gas, which comprises incorporating in the material an alkali metal salt of phthalic acid.

References Cited in the file of this patent UNITED STATES PATENTS 1,914,945 Ellis June 20, 1933 

